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This study investigated genetic diversity and genetic structure of six wild crucian carp populations collected from Heilongjiang River, Yangtze River, Fenghua River and Huaihe River by 8 genome microsatellites (G-SSR) and 8 transcriptome microsatellites (EST-SSR). The mean Na, Ne, Ho, He and PIC of the eight G-SSR loci were 22, 12.9, 0.769, 0.893 and 0.879, respectively. Fst values ranged from 0.008 to 0.085, indicating that there were different degrees of genetic differentiation among the six wild crucian carp populations, among which two populations from the Heilongjiang River system were different from all the others. There was no significant genetic differentiation among the four populations in the Yangtze River, Fenghua River and Huaihe River. The Nei’s genetic distances of six wild crucian carp populations were between 0.203—0.701. UPGMA cluster analysis and Bayesian analysis supported that six crucian carp populations could be divided into two large branches with two populations from Heilongjiang water system as one group while the others as another group. The average Na, Ne, Ho, He and PIC of the eight EST-SSR loci were 19, 9.5, 0.728, 0.870 and 0.855 respectively. The Fst values and Nei’s genetic distances among the six populations were between 0.005—0.084 and 0.117—0.683, respectively. Genetic differentiation analysis, UPGMA cluster analysis and Bayesian analysis based on EST-SSR markers also separated six populations of crucian carp into two major groups: the Heilongjiang water system group as well as the Yangtze River, Fenghua River and the Huaihe River system group. Based on G-SSR and EST-SSR markers, the average polymorphism information content (PIC) of the six crucian carp populations ranged between 0.786—0.864 and 0.761—0.833, respectively, indicating that all the six wild crucian carp populations had a high genetic diversity. Although the polymorphism of the EST-SSR markers was slightly lower than that of the G-SSR markers, the two types of SSR markers revealed similar genetic structure and pattern of differentiation for crucian carp in three major waters of China. This study provides basic and new information for the conservation of crucian carp germplasm resources and the evaluation of EST-SSR markers in genetic studies of fish populations.
Four full length Wnt cDNA sequences, designated Wnt5a, Wnt5b, Wnt7a and Wnt9b, were amplified by RT-PCR and RACE approaches from yellow catfish Pelteobagrus fulvidraco. The validated cDNAs of Wnt5a, Wnt5b, Wnt7a and Wnt9b were 1984, 2905, 2158 and 1622 bp in length, encoding peptides of 375, 375, 350 and 358 amino acid residues, respectively. The amino acid alignment and phylogenetic analysis revealed that Wnt sequences were relatively conserved among different vertebrates. All Wnt mRNAs were expressed in tested tissues (brain, spleen, kidney, gill, heart, muscle, mesenteric fat, liver and ovary) but with variable levels. Cu exposure for 28 days highly induced Wnt7a mRNA levels only at 30 μg Cu/L group. Cu exposure had no impact on mRNA levels of Wnt5a, Wnt5b and Wnt9b at day 28. On 56-day Cu exposure, mRNA levels of Wnt5b were not lowest at 60 μg Cu/L group and Wnt9b were the highest at 30 μg Cu/L group. Wnt5a and Wnt7a showed no significant differences among three groups. The present study indicated that functional differentiation exists in members of Wnt family, and some members may mediate the effect of Cu exposure on ovary development of yellow catfish.
Peptidoglycan recognition proteins (PGRPs) are a class of pattern recognition receptors that are highly conserved from invertebrates to mammals. So far, PGRP is rarely reported in vertebrate species except for bony fish and mammals. This study constructed the eukaryotic expression plasmid of PGRP-S, a short peptidoglycan recognition protein in Chinese giant salamander, and explored its functins. Sequence analysis showed that the N-terminal of PGRP-S had no signal peptide, but had two closely spaced cysteine residues and two Zn2+ binding sites. Moreover, PGRP-S could be secreted to the exterior and also be retained within the cells. In vitro antibacterial experiments revealed that overexpression of PGRP-S significantly inhibited the proliferation of Edwardsiella tarda in HEK293T cells intracellularly and extracellularly. In addition, overexpression of PGRP-S enhanced NF-κB promoter activity and bound Lys-type and Dap-type peptidoglycan but without degradation ability.These results indicate that the Chinese giant salamander PGRP-S is functionally similar to mammalian PGRP-S.
The density gradient method was used to isolate lymphocytes from peripheral blood of Cynoglossus semilaevis, and the isolated lymphocytes were cultured in complete DMEM medium (with 0.3 μg/mL PHA) for 3—4 days. Peripheral blood lymphocytes were separated to non-adherent lymphocytes and adherent lymphocytes using self-made nylon hair column. Non-adherent lymphocytes specifically bind with mouse anti-human FTIC-CD3 monoclonal antibody, while adherent lymphocytes specifically bind to anti-human FTIC-CD19 monoclonal antibody.TCRβ specifically expressed on non-adherent lymphocytes. Taken together, non-adherent lymphocytes were confirmed as T lymphocytes. The results of qRT-PCR showed that TCRβ was expressed in all detected 13 tissues with high expression level in the intestine, stomach, spleen, head kidney and the lowest level in muscle. The expression of TCRβ gene was significantly induced in the liver, spleen and gill with peak level at 72—96h afterV. Anguillarum infection. These results indicate that TCRβ gene plays an important role in adaptive cellular immune response.
To explore the molecular structure and biological function of SRBI in the process of carotenoids accumulation in Meretrix meretrix, we cloned cDNA of Mm-SRBI by SMART RACE technique and conducted the bioinformatics, expression analysis and intron amplification. The full length cDNA of Mm-SRBI is 1723 bp that contains a complete 1515 bp ORF encoding 504 amino acids with one functional domain of Mm-SRBI protein (CD36). Mm-SRBI is highly homologous with Mimachlamys nobilis and shares 55% similarity in amino acid sequence. It shares 34%—40% similarity with vertebrates. We also amplified 12 introns of Mm-SRBI, which followed the principle of GT-AG. Mm-SRBI gene expressed in all six tested tissues with the highest level in mantle (P<0.01), suggesting thatMm-SRBI gene maybe relate to high carotenoid in mantle. Moreover, the expression of Mm-SRBI gene in red shell strain was significantly higher than that of white shell strain (P<0.05). In conclusion, this study provides helpful foundation to explore the shell colors on this species.
Rock scallop Crassadoma gigantea was introduced to China in 2012, and was successfully bred in 2015. It is in the stage of popularizing culture now. To understand the genetic relationships and the genetic variations among C. gigantea, Argopecten irradians, Chlamys farreri, and Patinopecten yessoensis, the whole sequences of ITS1 and 5S rDNA were sequenced after the amplification by PCR. The sequence characterization, genetic diversity, genetic distance, and phylogeny were determined by using a suite of biology softwares. Based on the sequences of ITS1, the numbers of haplotype and polymorphic sites, haplotype diversities, nucleotide diversities, and average nucleotide differences were varied from 2 to 6, 1 to 12, 0.425 to 0.800, 0.00081 to 0.00486 and 0.366 to 2.44, respectively. In addition, based on the sequences of 5S rDNA, their same genetic variation parameters varied from 2 to 5, 1 to 14, 0.533 to 0.841, 0.00108 to 0.1058 and 0.533 to 5.726, respectively. The result showed that all these four species had a low diversity level (π<0.01). Based on the sequences ofITS1 and 5S rDNA, the genetic distance were varied from 0.040 to 0.124, and 0.043 to 0.457, respectively, which demonstrated that C. gigantea appeared to be closely-related to P. yessoensis. Meanwhile, phylogeny trees of the genetic distances confirmed the genetic relatedness between C. gigantea and P. yessoensis. This work would provide basic information for future studies on germplasm resources management, as well as on the genetics and breeding strategies of C. gigantea.
To study the function of bursicon gene in Caridina during molting and cuticle formation, its open reading frame (ORF) containing two subunits genes were amplified by PCR respectively. The ORF of bursicon-α is 441 bp in length, encoding a protein with 146 amino acid residues. The ORF of bursicon-β is 411 bp in length, encoding a protein with 136 amino acid residues. The dynamic changes in the expression of both bursicon subunit genes during the molt cycle in Caridina have been analyzed by the real-time quantitative PCR. Relative expression of both bursicon-α and bursicon-β had different levels in different stages of the molt cycle, which increased through premolt stage (D stage) and reached their peak level at the D3 stage. The mRNA accumulation decreased to its lowest level at the molt stage (E stage). RNA interference-mediated knockdown of bursicon-α and bursicon-β retard the molting process and ecdysis behavior of Caridina. The cuticle of dsRNA-treated Caridina was thinner than that in the control group. These findings demonstrate that bursicon is involved in the thickening and hardening of cuticle in newly formed exoskeleton. Moreover, bursicon plays an important role in molt cycle.
The Onychostoma belongs to cyprinid group and contains 19 species from essentially morphological classification. However, the molecular phylogenetic relationship of Onychostoma, was not very clear. Here, we presented molecular phylogenetic analysis of 8 species in Onychostoma based on the whole mitochondrial genome sequence with Danio rerio and Spinibarbus denticulatus as outgroups. The results indicated that Onychostoma did not appear monophyletic which included 3 groups: Onychostoma macrolepis, Onychostoma lini andOnychostoma barbatum. O. barbatulum in clade 1, Onychostoma gerlachi and Onychostoma simum in clade 2, Onychostoma rara and Onychostoma alticorpus in clade 3. The result was roughly the same as the traditional morphological classification, which divides Onychostoma into three branches. The mitochondrial whole genome was firstly used in Phylogenetic research of Onychostoma and filled the shortage of Phylogenetic studies of this genus.
To investigate the effects of fatty acids on the proliferation and differentiation of preadipocytes from Nile tilapia (Oreochromis niloticus), 100 μmol/L Palmitic acid (PA), Oleic acid (OA), Linoleic acid (LA) and α-Linolenic acid (LNA) were used. SRB (Sulforhodamine B) staining and oil red O staining were used to detect cell proliferation and preadipocyte differentiation. The expression level of genes related to proliferation and differentiation was detected by Real-time qPCR. The results showed that exogenous fatty acids promoted the preadipocyte proliferation in 8 days, and significantly increased the expression level of proliferation related genes (c-fos and c-myc), lipolysis related genes (ATGL) and adipogenesis related genes (PPAR, CD36 and FAS) (P<0.05). In addition, fatty acid inhibited preadipocyte differentiation into adipocyte by decreasing lipid droplets area and increasing the lipid droplets number. During differentiation, expression level of β-oxidation related gene (CPT-1a) significantly increased (P<0.05), while the expression level of lipolysis related genes (ATG) and adipogenesis related genes (PPARγ and FAS) declined. Our results showed that exogenous fatty acid promoted the proliferation and inhibited preadipocyte differentiation. In the process of proliferation, excess fatty acids stored in the preadipocyte that could be metabolized by lipolysis and β-oxidation during adipogenesis to help cells adapt to high concentrations of fatty acids in the environment. While during the differentiation, the exogenous fatty acids can inhibit adipogenesis and lipolysis of adipocyte and promote β-oxidation to reduce adipocyte differentiation.
To study the effects of α-ketoglutarate (AKG) supplementation in low-phosphorous diets on growth performance, body composition and serum biochemical indexes of Songpu mirror carp, triplicate groups of Songpu mirror carp (6.67±0.84) g were fed with practical diets containing available P (AP) 0.73% (normal P) and 0.47% (low-P) with graded levels of 0, 0.4%, 0.8%, 1.2%, 1.6% and 2.0% of AKG to satiation for 8 weeks, respectively. The results showed that the feed coefficient (FCR) of the low phosphorus group was significantly higher than that of the normal phosphorus group (P<0.05), but the weight gain rate (WGR), specific growth rate (SGR), protein efficiency (PER), VSI, and CF were similar between normal P and Low-P groups (P<0.05). Compared with low P group,FCR of 0.4% AKG group and the levels of phosphorus and albumin (ALB) in 1.6% AKG group in normal P group were significantly increased (P<0.05), respectively. Compared with normal P group, ALT activity of the 0.8% AKG and AST activity of the 1.6% AKG in the low P group were significantly increased, respectively (P<0.05). AKG had no effect on serum other indexes (P>0.05). Compared with the normal phosphorus group, the content of crude ash and the deposition rate of calcium and phosphorus in the low phosphorus group decreased significantly (P<0.05). Compared with the low phosphorus group, the phosphorus deposition rate and bone calcium content of 0.4% AKG and bone phosphorus content of 0.8% AKG in normal P group increased significantly, respectively (P<0.05). Adding AKG in low phosphorus diet had no significant effect on other body composition indexes (P>0.05). Thus, the suitable supplementation of AKG in the low phosphorus diets can reduce theFCR and improve the content of calcium and phosphorus in bone of Songpu mirror carp.
A 52-day growth trial was conducted to evaluate the effects of different dietary lipids on the growth performance, lipid metabolism, and antioxidant ability of Brachymystax lenok. Fish with average initial weight of (22.19±1.10) g were fed with four experimental diets that contained fish oil (FO), colza oil (CO), palm oil (PaO), and soybean oil (SO), respectively. The lowest weight gain, specific growth rate, and the feed conversion ratio were observed with CO treatment, while the highest values of these parameters occurred at the experiments of FO and SO, with no significant differences between these two conditions (P>0.05). Crude protein and lipid in the muscle ofBrachymystax lenok were not affected by lipid sources (P>0.05). However, the DHA level ofBrachymystax lenok fed with SO increased, which indicated that Brachymystax lenok had the ability to desaturate and elongate from 18:3n-3 to 22:6n-3. Compared to which fed with FO, an increase of TG and decrease of TC were observed in the serum of Brachymystax lenok fed with plant oils. In addition, the mRNA expression of Δ6 Fad in the liver of those fed with plant oils also increased, but the mRNA expression of ACC1 and FAS decreased. The values of ROS, MDA, GPx and TBARS in liver were significantly affected by different lipid sources (P<0.05). The results suggest that FO and SO could be used in the diet for juvenileBrachymystax lenok, but CO and PaO are unsuitable as single lipid sources for juvenile Brachymystax lenok.
Sinibotia reevesae, an endemic fish, live only in the upper reaches of the Yangtze River. To study nutritional composition in muscle during different growth phases, the main nutrient components in the muscles of age 1, 2 and 3 farmed (fed formulated feed) S. reevesae were analyzed, and the nutritional value and product flavor were evaluated. The general nutrient compositions were determined by routine methods, the amino acid compositions were measured with an amino acid analyzer and the fatty acid compositions by gas chromatography-mass spectrometry (GC-MS). The results showed that the contents of crude protein and crude fat in S. reevesae muscles increased with fish growth. With the increase of age, the moisture content decreased, whereas the contents of crude protein and crude fat increased. The crude protein in muscles of age-group 3 was significantly higher than that of the other two groups (P<0.05), while no significant difference was found in crude protein content between age-group 2 and 3 (P>0.05). The contents of different amino acids in muscles ofS. reevesae among 3 groups were stable. Glutamic acid, aspartic acid and lysine were the most abundant among 16 kinds of amino acids detected in muscles of each group. The essential amino acid index (EAAI) and the ratio of branched chain amino acid to aromatic amino acid (F value) of S. reevesae were very high. According to nutrition evaluation in amino acid score (AAS) and chemical score (CS), the first limiting amino acid for muscles of S. reevesae during different growth phases was valine acid. Totally 7 saturated fatty acids (SFA), 6 mono-unsaturated fatty acids (MUFA), and 7 poly-unsaturated fatty acids (PUFA) were found in dry muscles of S. reevesae from each group. The content of SFA was significantly lower than that of unsaturated fatty acids (UFA) (P<0.05), and the total content of MUFA, especially C18:1n9c, was significantly higher among UFA. PUFA in age-group 2 was significantly higher than that of the other two groups (P<0.05). The total content of EPA and DHA was lower than other Cobitidae fishes with the tendency to descend with the increasing age. These results indicate thatS. reevesae is a kind of high nutritional value, delicious, and high quality fish, and that S. reevesae in age 2 and 3 age are great for consume because of higher contents of crude protein and crude fat, better amino acid and fatty acid compositions in muscle.
The taxonomic status of Brachymystax lenok tsinlingensis Li, distributing in Qinling area of China, is controversial since it was found. In this study, the morphological differences among three Brachymystax groups (B. lenok lenok (Pallas, 1773) and B. tumensis (Mori, 1930) from Amur river basin and B. lenok tsinlingensis (Li, 1966) from the Qinling area) were investigated, including five meristic characters and thirty-four standardized morphometric characters through multivariate morphometrics methods. Results of one-way ANOVA showed that five meristic characters and thirty-two standardized morphometric characters were significantly different (P<0.01) among three groups. Principal component analysis indicated that the cumulative contribution of the top three principal components was 92.779%. Effective linear discriminant formulas were obtained from fourteen standardized morphometric characters, with the discriminating accuracy of 99.4% in the three groups. The tree diagram of these groups based on the squared Euclidean distance showed thatB. lenok tsinlingensis had a close distance with B. lenok lenok, but it is distant from B. tumensis. The coefficient of difference (CD) for the outer gill raker number in the first gill arch between B. lenok tsinlingensis and B. lenok lenok is larger than the threshold value of 1.28, and the CD for the thirty-one standardized morphometric characters and two meristic characters in B. lenok tsinlingensis and B. tumensis was also greater than 1.28. According to the results listing above, and the geographical isolation of B. lenok tsinlingensis together with its morphological differences from B. lenok lenok and B. tumensis, it is deduced that the morphological difference between B. lenok tsinlingensis in Qinling and B. lenok lenok in Amur river basin has at least reached subspecies level.
The swimming ability is a fundamental organismal trait to influence growth, survival and even the Darwinian fitness of fish. Energy metabolism involves oxygen uptake, locomotor capacity includes aerobic swimming performance and anaerobic swimming performance, which exhibits great variations in these two physiological functional traits. Trade-off may occur when these two traits can not be optimized simultaneously since aerobic and anaerobic swimming performance pose conflicting demands on the same morphological feature of design. The present study examined the intra-individual variations and phenotypic trait correlations of swimming ability of the cyprinid fish, and investigated the effects of different acceleration speed on the constant acceleration swimming capacity in the cyprinid fish. Swimming performance of the juvenile crucian carp (Carassius auratus) including critical swimming speed (Ucrit), and gait transition speed (Ugt) was performed in a Ucrit test. The metabolic rates including resting metabolic rate (RMR), maximum metabolic rate (MMR), aerobic scope (AS=MMR–RMR) as well as factorial aerobic scope (FAS=MMR/RMR) were measured by both of theUcrit test and the test of excess post-exercise oxygen consumption (EPOC). A constant acceleration test (Ucat) was employed to examine the Ucat and Ugt in the juvenile crucian carp at four acceleration rates (0.083, 0.167, 0.250 and 0.333 cm/s2). Our study found that Ucrit were correlated with MMR and AS with the exception of RMR while Ugt was not related to any parameters of metabolic rates (MMR, AS and RMR) in the juvenile crucian carp. There were no significant difference in parameter average of metabolic traits (MMR, AS and FAS) between two induced exercise methods, and high repeatability was detected in intra-individual level between the two methods. Distinct correlations were found among traits of metabolism. The Ucrit and Ugt conducted by Ucrit test were smaller than those conducted by Ucat test. The acceleration rate had a determinable influence on Ucat but not Ugt. Ugt correlated positively with either Ucrit or Ucat and the constant acceleration swimming capacity had repeatability among four acceleration rates. Ucat was positively correlated to the anaerobic metabolism contribution (Ucat–Ugt) by the acceleration swimming test at three acceleration rates with the exception of 0.333 cm/s2. However, the aerobic metabolic capacity (Ugt) was negatively related to the anaerobic metabolic capacity (Ucat–Ugt) in the juvenile crucian carp by the Ucat test. The study suggested that no methodological difference could be found in aerobic capacity by the test of Ucrit and EPOC, and that correlation among traits of energy metabolism and constant individual difference in acceleration swimming performance could be found in the juvenile crucian carp. Performance trade-off was detectable between aerobic metabolic capacity and anaerobic metabolic capacity in this species.
Accelerating flow generally exists during fish downstream migration passage, which will affect swimming behavior of individual fish. In this study, the swimming behavior of juvenile silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) during downstream migratory were tested under two types of accelerating flows (Ⅰ: 22—55 cm/s, Ⅱ: 25—60 cm/s). The objective of this experiment was to quantify the swimming behavior, including downstream pass rate, the way of downstream movement, and the time spent in each area. The preferred flow velocity was measured by the percentage of residence time (Ft). The result showed that the fish performed two kinds of downstream behavior in accelerating flow, which were " direct” and " non-direct”. The direct downstream rate of silver carp and bighead carp were 35.71% and 30% in Ⅰ, and 45.83% and 59.09% in Ⅱrespectively. During the non-direct downstream movement, silver carp spent significantly longer time in the flow less than 30 cm/s under both I and II flow conditions (P<0.05), which indicated that the preferred water velocity of silver carp in the tests was less than 30cm/s. The time spent by bighead carp was significant longer in the flow velocity less than 30 cm/s and 50—55 cm/s under flow conditionⅠ than in flow with other velocity (P<0.05), and under flow condition II, the time was longer in the flow velocity less than 30 cm/s (P<0.05), which implicated that the preferred water velocity of bighead carp in the test was less than 30 cm/s. Based on the results from two types of accelerating flow conditions, it showed that there was significant difference (P<0.05) in the residence time between silver carp and bighead carp in the flow with velocities less than 30 cm/s and 50—55 cm/s, but there was no significant difference (P>0.1) in medium and high velocity conditions. The study demonstrated that the accelerating flow can affect the swimming behavior of individual fish during downstream migration, and there is some interspecific difference in the ways of downstream migration and preferred velocity between silver carp and bighead carp.
To study the tolerance of Percocypris pingi retrodorslis to temperature, pH, and salinity, the juvenile Percocypris pingi retrodorslis were used as experimental objects. A single factor static acute toxicity test was used to study their tolerance to temperature, pH and salinity. The experimental results showed that their tolerance on temperature ranged from 0 to 32℃, and the lethal high and low temperature was 32℃ and 1℃, respectively. The optimum growth temperature was between 8 and 27℃. In addition, the optimum growth pH was 5.0—9.0. However, the juvenile fish began to die when pH was higher than 9.5 or lower than 4.7 (within 96h after treatment). The effects of different alkalinity on the survival of juvenile fish have significant difference (P<0.05), after the treatment for 24h, 48h, 72h and 96h, but there was no significant difference effects on the survival at different acidity level (P>0.05). TheLC50 of acidity for the juvenile fish was 3.90, 3.96, 4.15 and 4.40 after treated for 24h, 48h, 72h and 96h, respectively. The LC50 of alkalinity was 11.20, 11.10, 10.98 and 10.89 after the treatment of 24h, 48h, 72h and 96h, respectively. The juvenile fish began to die when salinity was higher than 7.5, and the effects of different salinity on the survival of juvenile fish were significantly different (P<0.05). TheLC50 of salinity for juvenile fish was 10.30, 9.25, 9, 8.85 and 8.82 g/L at 12h, 24h, 48h, 72h and 96h after treatment, respectively, and two safe concentration (SC) levels were 0.89 g/L and 2.385 g/L. The Percocypris pingi retrodorslis has been listed as endangered species, and our data will provide a theoretical foundation for the artificial breeding and trans regional breeding of Percocypris pingi retrodorslis.
Pathogens are often found with Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis; YFPs) that live under captive and semi-natural conditions. To investigate the diagnosis and treatment of bacterial diseases of Yangtze finless porpoise, the pathogenic bacterium Staphylococcus aureus and Morganella morganii were isolated from naturally infected Yangtze finless porpoise that live under semi-natural conditions in Anqing Xijiang River. The drug-sensitivity tests of the pathogenic bacterium of the Yangtze finless porpoise demonstrated that pathogens are Staphylococcus aureu and Morganella morganii. The outcomes of treatments based on drug test results were effective. This study provides a good reference for the diagnosis and prevention of bacterial diseases of the Yangtze finless porpoise and dolphin.
The thresholds for the hearing of marbled rockfish (Sebasticus marmoratus) were studied using the auditory evoked potential (AEP) technique. The AEP responses to seven different sonic stimulations, whose tone burst frequencies are between 100—1000 Hz, from eight fishes were recorded by two subcutaneous electrodes (Tucker Davis Technologies). Our results showed that marbled rockfish were sensitive to the low frequency sounds ranging from 100 to 300 Hz, and the most sensitive sound frequency is 150 Hz, corresponding to the lowest hearing threshold of 70 dB re 1 μPa. The dominant frequency of the fish sound matches with their sensitive sound frequency range, which indicates that marbled rockfish are able to detect their own sounds, and the importance of acoustic communication among them. Meanwhile, low-frequency anthropogenic noise may affect their acoustic communication.
Germ cells, different from somatic cells, carry the hereditary information and can transmit it to next generation. The germ cells cryopreservation and culture are the key techniques for cell engineer breeding and genetic resource preservation. This study investigated the effects of cryopreservation of the testicular blocks or dissociated cells on the viability of male germ cells of American shad after 250 days using Hochest33342/Propidium Iodide (PI) staining. The results showed that the overall viability of germ cells from the testis blocks cryopreservation was higher than that of dissociated cells cryopreservation, suggesting that the tissue frozen could efficiently cryopreserve the germ cells at different stages in American shad. Moreover, the thawed germ cells of American shad were stained with PKH26 before transplantation into newly-hatched zebrafish fries (1 days post hatching). At the 5th day post transplantation, the donor cells were still detected in some recipients and some donor cells were co-localized with the endogenous PGCs of recipient, implying that the germ cells of American shad after a long-term cryopreservation still possess the properties of germ cells and could integrate to the genital ridge of zebrafish host. The findings of this study provide technological and theoretical basis for further investigations on germ cell development, culture and genetic resource preservation in American shad or other anadromous fish in wild field.
Based on the survey data collected in April 2015 via bottom trawl along Zhejiang coast, this study identified the species composition and dominant species, as well as analysed the resource biomass and density, and community diversity. In addition, the relationship between the community structure of snails and environmental factors was also explored in this study. The results showed that 27 snail species were identified, and they belong to 2 orders, 15 families and 21 genera. The dominant species were Turritella bacillum and Siphonalia spadicea; The average biomass and density were 246.64 kg/km2 and 27.75×103 ind./km2, respectively, whose distributions appeared to be inhomogeneous. However, the density in the northern area was lower than that in the middle-southern area. The average values for species abundance index (D), species diversity index (H′) and species evenness index (J′) were 0.36, 0.56 and 0.50, respectively, indicating the snail community diversity was on a low level. Species diversity index (H′) display spatial distribution pattern, but the other two indexes remained almost constant in the study area. The ABC curve showed that snail community was unstable in spring. According to the CCA analysis, the distribution of snail community was affected mainly by depth, bottom temperature and bottom dissolved oxygen in the surveyed area.
To investigate the effects of cadmium (Cd2+) on the feeding capacity and its mechanism of water flea, Daphnia magna, three experimental groups with different Cd2+ concentrations (0.01 mg/L, 0.05 mg/L and 0.09 mg/L) and one control group were set up in this study, and these groups were exposed for 24h and 48h, respectively. The effects of Cd2+ levels on the feeding and filtration rate, tissues accumulation of Cd2+, total antioxidant capacity (T-AOC), contents of malonyldialdehyde (MDA), and the activities of acetylcholine esterase (AChE) in D. magna were analyzed. The results showed that (1) the feeding and filtration rates of D. magna decreased with increasing Cd2+ concentrations. Especially, when the D. magna was exposed to 0.09 mg/L Cd2+ for 48h, the feeding and filtration rates dropped dramatically (P<0.05,P<0.01), with the feeding rate decreasing by 43.89% compared to the control group. (2) With the increase of Cd2+ concentration, the accumulation of Cd in tissues was significantly higher in the experimental groups than that in the control group. (3) The total antioxidant capacity (T-AOC) and content of MDA in the water flea increased gradually with the concentration level of Cd2+. In the group with Cd2+ concentration of 0.09 mg/L, the levels of T-AOC and MDA increased significantly (P<0.05) compared to the control group. T-AOC was negatively correlated with the feeding rate whose correlation coefficientR2 were 0.9521 and 0.9389, respectively. (4) The activity of AChE decreased with increasing Cd2+ concentration, especially when D. magna were exposed to higher concentrations of 0.05 and 0.09 mg/L (P<0.05). The results indicated that Cd2+ stress not only caused oxidative damage to water flea, but also induced the abnormal conduction function to the nerve system, which would result in inhibition of feeding behavior in D. magna.
Phytoplankton is an essential component for the functioning of material cycle and energy flow which accounts for half of earth’s primary production. Meanwhile, phytoplankton community structure and distribution are important indicators of water environment and its quality. Identifying the main factors driving phytoplankton community structure is essential for better understanding and therefore managing freshwater ecosystem. Hence, we investigated phytoplankton community structure, morphology-based functional groups and temporal and spatial distribution of these groups among Lake Xiannü and inflow rivers during 2014—2015. There were 82 species of 7 phyla recorded, including 15 species of Cyanophyta, 33 species of Chlorophyta, 23 species of Bacillariophyta, 3 species of Pyrrophyta, 5 species of Euglenophyta, 2 species of Cryptophyta and 1 species of Chrysophyta. The average phytoplankton density and biomass were in ranges of 7.95×106—2.19×109 ind./L and 10.52—792.91 mg/L, respectively. Non-flagellated, with siliceous exoskeletons phytoplankton (Group Ⅵ, diatom) was the dominant species in river habitat in spring and autumn. Unicellular flagellates of medium to large phytoplankton (Group Ⅴ, Cryptophyta and Pyrrophta) was the dominant species in lake zones. Although biomass of Group Ⅵ phytoplankton was relatively high in different habitats, large filaments with aerotopes phytoplankton (Group Ⅲ) and large mucilaginous colonies (Group Ⅶ), such as Cyanophyta, increased significantly between summer and autumn. Analysis of the relationship between phytoplankton morphology-based functional groups and environmental factors found that the biomass of Group Ⅴ and Ⅵ was affected by the TN and TP concentration in winter and spring. In summer and autumn, phytoplankton of Group Ⅲ and Ⅶ were affected by multiple factors including water temperature, turbidity and TN and TP concentrations.
Arginine has been widely used in medicine and food industry. Synechocystis sp. PCC 6803, a unicellular cyanobacterium, synthesize amino acids and other compounds using nitrate or nitrite as the nitrogen source. In flue gases released by industrial production, NOx (nitrogen oxides) can react with water to form nitrate and nitrite, which can be utilized by cyanobacteria. Hence, creating high arginine producing strain of Synechocystis sp. PCC 6803 has a strong application prospects, in denitrification of industrial flue gases. This study reported the successful creation of a high arginine producing strain #13807-111-55 of Synechocystis sp. PCC 6803 by 0.8 g/L D-arginine and 0.2 g/L 6-azaruacil resistant mutants with UV mutagenesis. Compared with the parent strain #13807, extracellular arginine production per OD730 of #13807-111-55 increased 62.3-fold, reaching (0.76±0.1) mg/(L·OD730). Total arginine production per OD730 of #13807-111-55 increased about 6.0-fold, reaching (0.82±0.08) mg/(L·OD730). Extracellular arginine production per OD730 of the mutant was significantly higher than that of intracellular, showing that the strain was the arginine-secreting mutant with strong production potential.
To assess the diatom diversity of Lake Kanas, the largest freshwater lake in the Altay region, we analyzed a total of 36 diatom samples: 19 samples from the surface sediment in the lake, and 17 samples were the water of the lake, rivers and wetlands. In all, 123 taxa belonging to 46 genera were observed. Some of the 123 taxa listed are illustrated with LM and SEM photos. Among them, 13 are newly recorded species in China. They are Amphora indistincta Levkov, A. neglecta f. densestriata Foged, Asterionella edlundii Stoermer & Pappas, Discostella stelligeroides (Hustedt) Houk & Klee, Fragilaria capucina fo. sublanceolata-baikali Flower & Williams, Gomphonema makarovae Lange-Bertalot, Hippodonta geocollegarum Lange-Bertalot, Metzeltin & Witkowski, H. pseudorostrata Metzeltin Kulikovskiy & Lange-Bertalot, Nitzschia metzeltinii Lange-Bertalot, Placoneis opportuna (Hustedt) Chudaev & Gololobova, Sellaphora pseudobacillum (Grunow) Lange-Bertalot & Metzeltin, S. madida (Kociolek) Wetzel and Staurosira aff. sviridae Chudaev & Gololobova.
Euglena have important scientific value for studying biological evolution and chloroplast endosymbiosis and provide high value-added dietary supplements as well as high-quality feedstock for biofuel production. Studies of Euglena have been mainly explored by physiological and biochemical methods. With almost completed Euglena genome, we employed diverse OMIC techniques such as single cell RNA-seq, transcriptomic, proteomic, methylomic, and metabolomics to study the chloroplast development and the communication between chloroplast and nucleus. We hooked up some interesting genes and microRNA targets. Little progress has been achieved in genetic engineering of Euglena due to lack of efficient techniques for genetic operation. In here, we reviewed the methods in genetic transformation of Euglena, such as antibiotic biomarkers, biolistic, electroporation, glass beads and Agrobacterium transformation techniques, RNAi, potential CRISPR/cas9, and cpf1 genome editing, to provide a reference for functional genomics and biotechnology of Euglena.